Anesthesia, General
Conditions
Keywords
Muscle relaxants, Laryngeal local anesthetics, Laryngeal mask airway, Laryngeal Masks, LMA, Propofol, Elderly, Aged
Brief summary
Laryngeal mask airway (LMA) is currently the most widely used supraglottic airway device with advantages of simple and fast placement, reduced anesthesia drug use, more stable hemodynamics, and less throat discomfort after anesthesia compared to endotracheal intubation. Some studies claimed the use of muscle relaxants or local anesthetics (sprays or lubricants containing local anesthetics) for the throat before LMA placement can reduce the dosage of induction agents and postoperative throat complications. In modern society, more and more elderly people undergo elective surgery with the need of general anesthesia. However, they are the more vulnerable population with tendency of greater hemodynamic changes with more induction agent usage. Propofol is one of the most used induction agents which may lead to a drop in blood pressure. The objective of this study is to observe whether the dose of propofol and the changes in hemodynamics can be reduced by using muscle relaxants or laryngeal local anesthetics in elderly who receiving general anesthesia with LMA insertion.
Interventions
10% lidocaine spray 3 puff for the throat before induction
DRUGPlacebo of lidocaine spray
Normal saline spray 3 puff for the throat before induction
DRUGCisatracurium
Intravenous cisatracurium 0.12 mg/kg during induction
DRUGPlacebo of cisatracurium
Intravenous normal saline during induction
DRUGPropofol
The dosage of intravenous propofol for the first subjects was predetermined for each arm, and the dosage for the subsequent subjects would be determined according to the response of the previous subjects using the Dixon's up-and-down method with a step size of 0.25 mg/kg. If the subjects had no movement and stable hemodynamic status during and after the laryngeal mask airway (LMA) placement, the predetermined dosage of propofol for the subsequent subject would be decreased by 0.25 mg/kg. On the other hand, if the subjects had obvious movement, failure to LMA placement, and significant hemodynamic changes, the predetermined dosage of propofol for the subsequent subject would be increased by 0.25 mg/kg.
Sponsors
Chang Gung Memorial Hospital
Study design
Allocation
RANDOMIZED
Intervention model
FACTORIAL
Primary purpose
OTHER
Masking
TRIPLE (Subject, Caregiver, Investigator)
Eligibility
Sex/Gender
ALL
Age
65 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* American Society of Anesthesiologists (ASA) physical status I-III * Age: over 65 years * Elective orthopedic surgery undergo general anesthesia in supine position
Exclusion criteria
* Anticipated difficult airway (Mallampati score 3-4), limited mouth opening, intra-oral and pharyngeal pathology * Risk of pulmonary aspiration of gastric contents (full stomach) * Obesity (Body mass index \> 35) * Significant lung abnormalities (low lung compliance, high airway resistance, impaired oxygenation) * Loosening teeth * Allergic to Cisatracurium or Lidocaine * Failure in successful LMA insertion after second attempts
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Propofol requirement | one minute after propofol infusion | The minimal propofol requirement dose was defined as the median effective dose (ED50) of movement or increased mean arterial pressure (MAP) to no movement or stable MAP. The ED50 is the average of the crossover midpoints found during conducting the Dixon's up-and-down method. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Heart rate (HR) | 0 minute, 1 minute, 2 minute, 3 minute, 4 minute, 5 minute, 10 minute after LMA placement | Using the electrocardiogram monitor to collect the real-time heart rate |
| Oxygen saturation (SpO2) | 0 minute, 1 minute, 2 minute, 3 minute, 4 minute, 5 minute, 10 minute after LMA placement | Using the pulse oximeter to collect the real-time oxygen saturation |
| Peak pressure (P peak) of the airway | 0 minute after LMA placement | One of the monitoring parameter demonstrated on the mechanical ventilator |
| Mean pressure (P mean) of the airway | 0 minute after LMA placement | One of the monitoring parameter demonstrated on the mechanical ventilator |
| Ease of jaw opening | Procedure (At the same time of LMA placement) | A factor for evaluating the condition of LMA insertion |
| Ease of LMA insertion | Procedure (At the same time of LMA placement) | A factor for evaluating the condition of LMA insertion |
| Non-invasive blood pressure (NIBP) | 0 minute, 1 minute, 2 minute, 3 minute, 4 minute, 5 minute, 10 minute after LMA placement | Using the non-invasive blood pressure machine to collect the systolic blood pressure, diastolic blood pressure, and mean arterial pressure |
| Hiccups | Within 1 minute after LMA placement | Symptoms which suggest non-optimal condition of LMA insertion |
| Head or body movement | Within 1 minute after LMA placement | Symptoms which suggest non-optimal condition of LMA insertion |
| Laryngospasm | Within 1 minute after LMA placement | Laryngospasm is defined as airway obstruction with assumption that LMA is correctly placed, which is also a factor for evaluating the condition of LMA insertion |
| Attempts for LMA insertion | Procedure (At the same time of LMA placement) | The number of attempts for LMA insertion |
| Complications | One hour after LMA removal | Including sore throat, dysphagia, dysphonia |
| Coughing or gagging | Within 1 minute after LMA placement | Symptoms which suggest non-optimal condition of LMA insertion |
Countries
Taiwan
Outcome results
None listed